About 40 children in New Zealand have HIV (human immunodeficiency virus), statistics from Dunedin School of Medicine's Aids Epidemiology Group show.

Between 2005 and 2010, 978 adults were diagnosed with HIV, which can lie dormant for years and develops into Aids when the virus attacks the immune system. HIV is most commonly contracted through sexual intercourse. It can also be passed to children through childbirth or blood transfusions.

The story of Eve van Grafhorst, whose family moved to Hastings after she was victimised in Australia, helped shed light on the stigma around the virus.

Eve contracted Aids through a contaminated blood transfusion, the final one of 11 that were used to save her life after a premature birth.

But parents are still choosing not to speak out about their child's illness out of fear of others' reactions.

The situation was highlighted last month when the family of a 4-year-old boy with HIV said he was not welcome at Mokopuna Early Childhood Education and Care Centre in Whangarei. Centre management denied staff told his family he was not welcome, and his mother has since chosen to place him in another preschool.

Just two children with HIV are of preschool age in New Zealand, and like many parents of children with HIV, they like to keep their situation private.

The parents of a 9-year-old boy with HIV who spoke with the Sunday Star-Times had a better experience at their childcare centre.

They were hesitant to talk to anyone about their son's condition, and told only three staff members, family and best friends.

"They didn't have a problem at all, they helped me pass a difficult time."

Their son was diagnosed at 15 months after becoming ill. Unbeknown to his parents, who knew little about HIV, he had contracted the virus from his mother at birth.

They said that the way Mokopuna Childcare Centre treated the family of the four-year-old in the latest case was unnecessary.

"They have so many ways to say if they don't want the boy to be there. I can't understand why they had to let other families know."

There is no cure for HIV but patients are prescribed antiretrovirals that suppress the virus to low levels.

Their son's virus levels are kept low through daily medication, reducing the risk of infection to other people. He takes part in school sports, events, camps and extra-curricular activities and there have been no issues.

The 4-year-old in the Whangarei case also had viral loads which were undetectable. His levels were lower than 50 parts per million of blood, meaning there was a minimal chance of risk of infection, NZ Aids Foundation spokeswoman Dawn O'Connor said.

"Children with anaphylactic peanut allergies would require significantly more work than a kid with HIV," O'Connor said.

Positive Women national co-ordinator Jane Bruning said parents are even more afraid to speak out now following the Whangarei case.

"This is exactly the reaction they feared they would get."

Parents are not legally required to disclose to a school whether their child is HIV positive. Schools and early childhood centres are well equipped to care for such children by following the Ministry of Education's simple guidelines on dealing with infectious blood-borne illness such as hepatitis.

But they are also strongly recommended for all scenarios where blood is involved.

They include wearing disposable gloves when cleaning cuts and immediately placing blood-stained cloths and materials in a disposable bag. Waterproof plasters or bandages should be applied to disinfected cuts, and hands and surfaces must be cleaned and sterilised afterwards.

School policy enrolment packs also ask parents to notify their school when they are keeping their child home for notifiable highly contagious diseases such as chicken pox, measles or mumps.

Few children have been born with HIV since pregnant mothers can now be screened for the virus and receive treatment in their first trimester. Once born, the baby is washed and started on a precautionary course of treatment for six weeks to eradicate the virus.